Water heater lights but hot water is only lukewarm, never reaching the set temperature.

Safety: Gas adjustments must be done by licensed personnel. You may perform only basic cleaning.

Steps:

• Check temperature setting: Ensure the Sime control panel is set to an adequate DHW temperature (e.g., 50–60°C).
• Verify flow rate: Excessive flow can cause lukewarm water. Partially close the hot tap to reduce flow and see if temperature increases.
• Clean burner: With power and gas off, remove the burner cover and gently clean burner ports with a soft brush and vacuum.
• Consider descaling: If the unit is older and in a hard water area, arrange for professional descaling of the primary heat exchanger.

Professional help: If temperature remains low, a Sime technician should check gas pressures, valve modulation, and combustion.